Conventionally, there has been proposed an information input/output method of printing, on a medium surface, a dot pattern obtained by two-dimensionally arranging fine dots according to a predetermined rule instead of a barcode so as to allow inputting/outputting of a lot of information and programs, picking up them as image data by means of a camera, digitizing the data, and then outputting information such as speech.
For example, there has been proposed a method of storing provided code information and information corresponding to XY coordinates in a storage means in advance and outputting various information or executing programs by retrieving them from code information and XY coordinates read by an optical reading means (patent literatures 1 and 2).